Chapter 19. IPSec Site-to-Site Connections

This chapter and the next one cover some basics of VPN connectivity on your perimeter router. Because of space constraints in this book, I have decided to focus on two types of VPN connections: IPSec site-to-site (or LAN-to-LAN, sometimes referred to as L2L) and remote-access IPSec connections. I assume that you are already somewhat familiar with the IPSec standard and its components. Because a perimeter router is used in many cases to terminate VPN connections, I have included two chapters in this book on this topic. For more detailed information related to VPNs with Cisco products, look for my upcoming book The Complete Cisco VPN Configuration Guide (Cisco Press, 2005), which discusses in depth the setup and troubleshooting of VPNs using the Cisco 3000 series concentrators, routers, PIX firewalls, and software clients.

This chapter covers the following topics:

• IPSec preparation

• IKE Phase 1: the management connection

• IKE Phase 2: the data connections

• IPSec troubleshooting

• IPSec L2L connection example